MADRID, Spain (CNN) -- Five people were slightly wounded when seven bombs exploded in as many Spanish cities following warnings by Basque separatist group ETA, according to officials.

Monday's blasts came just three days after a similar warning was issued about five bombs in Madrid that later exploded.

A spokeswoman for Spanish Interior Ministry said two of the wounded people were police officers who were evacuating a cafeteria in the southern city of Ciudad Real when a bomb exploded.

One other person was wounded in Ciudad Real, and two more were wounded in the northern city of Santillana del Mar.

News reports said one of the two wounded in Santillan del Mar was a 5-year-old child.

Other bombs exploded in Avila, Valladolid, Leon, Malaga and Alacante, all at about 1.30 p.m. (1230 GMT) on Monday, the time indicated by phone calls to the Basque newspaper Gara.

After the phone calls, police dispatched officers to the locations indicated to minimize casualties.

The interior ministry said the injuries may have taken place because some of the bombs went off in different locations than warned of by ETA.

None of the sites bombed on Monday are within Spain's Basque Country, which comprises three provinces in the north of Spain that nationalists say are part of a Basque homeland including Navarra and three provinces in France.

Monday is Constitution Day, a Spanish national holiday to commemorate the 1978 constitution, and a series of events are planned across the country with top government officials attending.

Friday's bombs went off at five gas stations as hundreds of thousands of Spaniards were heading off for the weekend.

In those blasts, six people were slightly injured at two locations, including two police officers whose eardrums were hurt, according to Interior Minister Jose Antonio Alonso.

Alonso said the small blasts were apparently the work of ETA, in whose name a warning was issued about one hour before the bombs went off. The preliminary probe also pointed to ETA, the official said.

Government: Group weak

About 2.5 million Basques live in Spain, the Pyrenees mountain region along the border between Spain and France -- where they have lived for 5,000 years. Another half million live in France.

While Spain officially recognizes three Basque Provinces, separatists want another Spanish province, Navarra, to be included as well as part of southern France to create a homeland.

Authorities recently arrested top ETA leaders in France and seized huge caches of weapons and ammunition in raids.

Because of the crackdown, and with about 400 ETA members in prison, the Spanish government had led the public to believe that the group was weakening.

ETA, which has been blamed for more than 800 deaths in Spain since the 1960s, is designated a terrorist group by the United States and the European Union.

The bombings of commuter trains in Madrid in March that killed 191 people and injured 1,500 were initially blamed on ETA, but authorities later concluded they were carried out by Islamic extremists with links to al Qaeda.